HPC Engineer

Nebius is building a hyperscale AI cloud platform and we are seeking a Senior Systems HPC Engineer to contribute to the design, development, and optimization of large-scale GPU clusters. You will work across the full stack—from hardware and system software to networking (InfiniBand/RoCE), virtualization (KVM/QEMU), and distributed communication layers (MPI, NCCL). The role focuses on understanding system behavior across layers, identifying performance bottlenecks, and driving improvements for cluster construction, operation, tuning, and validation. Responsibilities include investigating performance issues under real workloads (training and inference), evaluating new hardware and tuning approaches, supporting escalations, collaborating with infrastructure, software, and hardware vendor teams (e.g., NVIDIA, Mellanox, Intel), and contributing to hardware and cluster qualification. Requirements include 5+ years in system-level software development with a focus on performance optimization, 3+ years of hands-on Linux experience, deep understanding of server architecture (PCIe, NICs, Linux kernel), and proficiency in one or more performance-oriented languages (C/C++, Go, Python). The team engages in coding interviews as part of the process.